Method of removing static



Oct. 9, 1928. 1,686,998

C. W. WOODRU FF METHOD OF REMOVING STATIC Original Filed Feb. 4, 1925 Charla-2 W. Wo r fif- Patented Oct. 9, 1928.

CHARLES W. WOODR'UIF, 0]! COLUMBUS, OHIO.

METHOD OF REMOVING STATIC.

Application filed February 4, 1925, Serial No. 6,813. Renewed February 11, 1928.

This invention relates to an improved method and apparatus for removing from radio reception stray and vagrant electrical impulses ordinarily known as static disturbances, the primary object of the invention being the provision of an improved system and apparatus whereby this object can be achieved in a simple, positive and effective manner.

For a further understanding of the invention reference is to be had to the following description and to the accompanying drawmg.

In said drawing:

The figure represents diagrammatically the relation between the cell used in the present invention and an accompanying radio receiving set.

As shown in the accompanying drawing use is made of acell 1 which, from a standpoint of construction, may be formed to comprise a casing 2, which may be composed of glass, hard rubber or other insulation. It will be understood that the cell may be of any suitable dimensions or that one or more of the same may be employed. The casing 2 is adapted to receive a solution of ammonium phosphate or other chemical substance in water or the solution may be made into a paste with some inert substance, the said liquid or paste being designated by the numeral 3. Within the casing there is arranged two electrodes, one electrode designated by the numeral 5 is preferably composed of aluminum and the other electrode designated by the numeral 4, is composed of lead. It will be appreciated that other metals which behave similarly to lead and aluminum when immersed in a solution or paste may be employed rather than those specifically enumerated herein. The two electrodes may be made of the same metal as for instance both of aluminum In order to adapt the invention to all degrees of intensity of interference, several cells similar to 11 may be employed. with well known means for throwing any desired number in series or parallel with each other.

This is unnecessary however with a proper design as to dimensions. Cell 1 1s shown connected in series with the set in the antenna circuit. By the inclusion of the cell or cells large impulses above a predetermined inten-- sity, e. g. the usual type of static, or extra loud signals. causes a marked increase in the resistance of the cell practically simultaneously with said impulses, while no or feeble increase of resistance is caused by signals be.

low said intensity.

What is claimed is:

1. In a radio receiving system, the combination with a collector circuit, of a receiving apparatus, and a serially connected electrolytic cell comprising an electrolyte and a plurality of relatively small metallic electrodes, the chemical nature of and relation between these elements being such that impulses in said collector above a predetermined intensity causes a material increase of resistance of said circuit only during the existence of said impulse, said cell being relatively nonresponsive to impulses below said intensity.

2. In combination with a signal receiving circuit, an electrolytic cell serially associated with a portion of said circuit traversed by both desired signals and also by impulses above a desired intensity, the elements comprising said cell being of such chemical relation as to materially increase the resistance of said circuit portion in response to said immlsr s.

I 3. A static reducing device adapted to be connected serially in the input of a radio receiving circuit, comprising an electrolytic cell containing an electrolyte, aluminum electrodes immersed therein, said electrolyte being of such material that the resistance of the cell is relatively unaffected by currents under a certain maximum value, but material- 1y increases its resistance to currents above said value.

In testimony whereof I aflix my signature.

CHARLES W. WOODRUFF. 

